Lead Pentester - SC Cleared

CBS Butler; Rowberrow; Hybrid; GBP 80,000 - 100,000; Full time

Benefits offered by this job

Hybrid working

Company benefits package

Training & certification support

Job summary

CBS Butler is seeking a Lead Penetration Tester/ CHECK Team Leader to join our Offensive Security team in Bristol. This role blends hands-on testing with technical leadership across Defence, Government and critical national infrastructure in high-assurance environments.

You will lead engagements, mentor junior testers, and help shape service offerings while ensuring compliance with NCSC CHECK standards. Hybrid working (2 days onsite) and a strong salary package are on offer.

Qualifications

• Current Crest CHECK Team Leader (CTL) qualification is essential.
• Excellent hands-on penetration testing experience across infrastructure, applications, cloud or other complex environments.
• Experience planning, leading and delivering penetration testing engagements.
• Excellent technical report writing and the ability to communicate findings to technical and non-technical audiences.
• Strong stakeholder management and client-facing consulting skills.
• Good understanding of cyber security frameworks, standards and best practices.
• Experience with scripting or automation using Python, PowerShell, Bash or similar.
• Strong analytical and problem-solving skills.
• Ability to obtain SC Security Clearance, potentially progressing to higher levels of clearance.
• Willingness to travel to customer sites when required.

Responsibilities

• Lead and deliver penetration testing engagements across infrastructure, web apps, APIs, cloud, OT and more.
• Plan and scope testing engagements, ensuring alignment with CHECK standards.
• Provide technical leadership and quality assurance across penetration testing activities.
• Produce detailed technical and executive reports with remediation recommendations.
• Collaborate with customers to understand security requirements and deliver testing solutions.
• Mentor junior penetration testers and CHECK Team Members.
• Contribute to development of offensive security methodologies, tooling and service offerings.
• Stay updated with emerging threats and testing techniques.

Skills

CHECK CTL qualification

Penetration testing

Infrastructure & cloud testing

Technical leadership

Report writing

Stakeholder management

Scripting (Python)

Scripting (PowerShell)

Scripting (Bash)

Travel readiness

Tools

Python

PowerShell

Bash

Job description

Lead Penetration Tester/CHECK Team Leader (CTL)Location: Bristol - Hybrid (2 days per week onsite)
Salary: £80,000 - £100,000 per annum + Company Benefits
Employment Type: Permanent

The Opportunity

We are looking for an experienced Lead Penetration Tester/CHECK Team Leader (CTL) to join a growing Offensive Security team within a leading defence and cyber security environment.

This is an exciting opportunity for a technically strong penetration testing professional to take ownership of complex security engagements across Defence, Government and Critical National Infrastructure.

You'll be working on challenging, high-assurance environments, helping to identify vulnerabilities, strengthen security controls and protect critical systems.

This position offers much more than hands-on penetration testing. You'll have the opportunity to provide technical leadership, mentor junior consultants, contribute to service development and help shape the future of an expanding Offensive Security capability.

Key Responsibilities

• Lead and deliver penetration testing engagements across infrastructure, web applications, APIs, cloud, wireless networks and Operational Technology (OT).

• Plan and scope testing engagements, ensuring alignment with NCSC CHECK standards and industry best practices.

• Provide technical leadership and quality assurance across penetration testing activities.

• Produce detailed technical and executive reports, clearly communicating vulnerabilities, business risks and remediation recommendations.

• Work closely with customers and key stakeholders to understand security requirements and deliver effective testing solutions.

• Support and mentor junior penetration testers and CHECK Team Members.

• Contribute to the development of offensive security methodologies, tooling, automation and service offerings.

• Stay up to date with emerging threats, attack techniques and vulnerabilities.

Essential Skills & Experience

• Current Crest CHECK Team Leader (CTL) qualification - essential.

• Strong hands-on penetration testing experience across infrastructure, applications, cloud or other complex environments.

• Experience planning, leading and delivering penetration testing engagements.

• Excellent technical report writing and the ability to communicate findings to technical and non-technical audiences.

• Strong stakeholder management and client-facing consulting skills.

• Good understanding of cyber security frameworks, standards and best practices.

• Experience with Scripting or automation using Python, PowerShell, Bash or similar.

• Strong analytical and problem-solving skills.

• Ability to obtain SC Security Clearance, potentially progressing to higher levels of clearance.

• Willingness to travel to customer sites when required.

Desirable Experience

• Existing SC or DV Security Clearance.

• Experience working within Defence, MOD, Government or National Security environments.

• Additional certifications such as Crest CCT, OSCP, OSEP, OSWE or CRTO.

• Cloud penetration testing experience across AWS, Azure or GCP.

• Operational Technology (OT/ICS) security testing experience.

• Experience developing penetration testing tools, automation or frameworks.

• Knowledge of NCSC CAF, NIST, ISO 27001 and MITRE ATT&CK.

• Experience mentoring junior penetration testers or conducting technical quality assurance.

What's on Offer?

• Competitive salary of £80,000 - £100,000 per annum.

• Hybrid working - just 2 days per week onsite in Bristol.

• Company benefits package.

• Access to industry-recognised training, conferences and professional certification support.

• Opportunities to work on technically challenging projects across Defence, Government and Critical National Infrastructure.

• Exposure to a wide range of technologies, security environments and emerging threats.

• Opportunities to contribute to offensive security research, tooling and innovation.

• Genuine scope to influence technical direction, service development and the growth of the wider Offensive Security function.